Alina Grzanka(1,2), Dariusz Grzanka(1)

Distribution of Actin in Etoposide-Induced Human Leukemia Cell Line K-562 Using Fluorescence and Immunoelectron Microscopy Technique

1)Department of Clinical Pathomorphology, University School of Medical Sciences,
2)Department of Biology and Environment Protection, Bydgoszcz University of Kazimierz Wielki, Bydgoszcz

Abstract

Localization of actin was studied in erythroleukemic cell line K-562 after treatment with etoposide for 72 hours in a range of concentrations 0.02 - 200µM/L. Actin was visualised by fluorescence microscopy and streptavidin-gold method. These findings indicate that changes in actin after treatment with etoposide were dose-dependent. Significant changes in the cellular distribution of F-actin in K-562 cells were obtained after treatment with 20 and 200µM/L etoposide. In comparison with control cells, the number of the cells decreased and cells were larger especially at 200µM/L. F-actin was diffusely distributed throughout the cell at 20µM/L. Treatment of cells with 200µM/L etoposide showed F-actin diffusely distributed throughout the cell with local actin assemblies and also at the cell periphery. Immunogold labelling of actin was observed in cells treated with all doses of etoposide and control cells. Labelling was found in the nucleus and also in the cytoplasm. At the ultrastructural level, cells treated with 200µM/L etoposide showed protrusions at the surface, in which increase of actin was often observed. Etoposide causes changes in actin distribution of K-562 cells, and the changes in expression of actin were not only restricted to cell with features of apoptosis.